The invention concerns a refrigerant compressor with a cylinder block, a valve plate, a pipe connectable or connected with a suction muffler, a cover covering the valve plate, a first sealing between cover and valve plate and a second sealing between valve plate and cylinder block. The invention further concerns a method for assembling a refrigerant compressor with a cylinder block and a valve plate, the valve plate being, on the side opposite the cylinder block, covered by a cover, which has an opening for the adoption of a pipe, which is connected or connectable with a suction muffler.
The invention particularly concerns a hermetically enclosed refrigeration compressor, comprising an electric motor, which, by means of a rotating shaft and a crank disc connection, drives at least one piston to a reciprocating movement in a cylinder block, the cylinder block being closed by a valve plate, which forms the basis of suction and pressure valves, the valve plate being, on the side opposite the piston, covered by a cover, which has an opening for the adoption of a pipe, which is connected with a suction muffler. WO98/22712 describes an electric compressor, in particular for domestic refrigerators, with a cylinder body, a cylinder head, a valve plate, which is arranged between head and body of the cylinder, and which is provided with a gas suction opening. A muffler is arranged between the inner recess of the compressor housing and the head of the cylinder. The muffler is formed by a central gas suction body and an extended part, which extends away from the body and has an opening for the discharge of the gas contained in the muffler, the opening being adapted to exact engagement with the suction opening of the valve plate. On the outside, the head has a hollow seat or a recess, which is accessible in the direction of the inner volume of the compressor. The extended part of the muffler is adapted for fixed and stable placement in the recess, in a position that permits the corresponding opening to have an exact and tight engagement with the opening of the valve plate, to create a mutual connection between the inside of the muffler and the inside of the cylinder body, and the head is shaped so that it leaves part of the valve plate arranged under it, surrounding the suction opening, uncovered.
This will ensure an optimum gas suction path, as the pipe of the suction muffler is only secured in relation to the valve plate by means of a projection. As the suction muffler is mounted after the cover, a little space must always be available between the members with regard to the mounting, and there is a risk that the pipe of the suction muffler can rotate around the projection, meaning that it would become wry and offset in relation to the suction opening of the valve plate. Therefore, the opening in the pipe of the suction muffler is larger than the suction opening. However, this gives rise to an edge, which causes an eddy formation in the suction gas. Thus, the suction opening gets an active flow area, which is substantially smaller than the geometric area of the opening. The problem can be further aggravated, when the sealing between valve plate and cover is wry or offset.
When producing compressors, a very high accuracy is required, when an optimum mounting or assembling of the compressor top part is desired. Very narrow production tolerances are required. After the welding of the hermetic housing, the compressor can be exposed to a rather careless treatment during transport, which causes the risk that, for example, a suction muffler is displaced, so that the pipe of the suction muffler no longer has the optimum placement in relation to the suction opening. Therefore, the compressor in question will work during its whole life at reduced efficiency.
As the suction muffler is a rigid body, an undesired rotation of the suction muffler will influence its suction pipe. This gives a bad adaptation to the compressor pot, and the efficiency of the compressor will be reduced for its whole life. Further, this bad adaptation can have a negative influence on the noise level of the compressor.
It can be seen that the assembling of the compressor top part or the mounting of the compressor top part on the cylinder block, respectively, can have a substantial influence on the efficiency and the life of the refrigerant compressor. This also applies, when the parts forming the cylinder block or the compressor top part are produced with a relatively high accuracy. A sufficient accuracy in the production of the individual parts is anticipated in the following.